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by ejolson
Sat Dec 14, 2019 1:56 am
Forum: General discussion
Topic: In a Right Pickle!. :lol:
Replies: 12
Views: 545

Re: In a Right Pickle!. :lol:

I can and will link you to the page where the item was bought from so then you will see i am NOT at fault with any kinda description or images supplyed. So why haven't you done that already? Please post a link to the exact SSD adapter you have. ...which appears to be a USB2 to m.2 adapter rather th...
by ejolson
Fri Dec 13, 2019 6:13 pm
Forum: General discussion
Topic: In a Right Pickle!. :lol:
Replies: 12
Views: 545

Re: In a Right Pickle!. :lol:

I can and will link you to the page where the item was bought from so then you will see i am NOT at fault with any kinda description or images supplyed. The image you link looks like https://www.startech.com/HDD/Adapters/usb-m2-converter-raspberry-pi~PIB2M21 which appears to be a USB2 to m.2 adapte...
by ejolson
Fri Dec 13, 2019 3:56 pm
Forum: Troubleshooting
Topic: Pi Zero W unreachable over network after a few hours
Replies: 3
Views: 58

Re: Pi Zero W unreachable over network after a few hours

I have been running Owncloud on a pi zero W with a static ip for a few months with no problems. Recently while getting support from my ISP, the tech support reverted some settings including the SSID and password of the 2.4 GHz wifi on my modem router. I don't know what else was reset in the router ...
by ejolson
Fri Dec 13, 2019 5:11 am
Forum: Advanced users
Topic: Secure app running on Pi
Replies: 9
Views: 360

Re: Secure app running on Pi

We would like to hear any suggestions of prior experiences. The common way to protect code these days is to run the part that needs to be secured in the cloud. Prior experience can be learned from the case study of GEOS. As described here The original GEOS was copy protected in three ways: The orig...
by ejolson
Fri Dec 13, 2019 4:03 am
Forum: General discussion
Topic: New Pi 4B as a laptop - questions plz
Replies: 10
Views: 292

Re: New Pi 4B as a laptop - questions plz

Also, any news on upgrade of USB on Raspberry Pi keyboard to USB 3.0 or 3.1 any time soon? There wouldn't be any point to doing that. USB 2.0 is far faster than anyone can type, even if you include mouse data. The official Pi keyboard has an integrated USB hub. It makes good sense to me to have a k...
by ejolson
Fri Dec 13, 2019 2:15 am
Forum: Troubleshooting
Topic: Random speed slowdown reading files from connected usb hard drive on rpi3 (not a network problem)
Replies: 19
Views: 879

Re: Random speed slowdown reading files from connected usb hard drive on rpi3 (not a network problem)

I booted debian on the desktop, connected the 4tb drive and configured samba . Streams perfectly no buffering. So I guess is not the drive? I think the default Samba protocol and encryption level changed in the last year or two. Maybe the 3B can't efficiently stream the more secure versions. I thin...
by ejolson
Thu Dec 12, 2019 4:16 am
Forum: General programming discussion
Topic: Tatami Pi Fun.
Replies: 181
Views: 5621

Re: Tatami Pi Fun.

Anyway, I have indeed Rustified a couple more loops. They don't all get longer like that example. With the result that prune.rs now runs a tad faster on my PC than prune.c. Okay, I'll look in your Rust repository and pull something soon. The idiomatic version looks a bit loopy to me. Wouldn't it be...
by ejolson
Wed Dec 11, 2019 10:04 pm
Forum: General programming discussion
Topic: Tatami Pi Fun.
Replies: 181
Views: 5621

Re: Tatami Pi Fun.

I don't know about you but that gives me headache. I did not see any effect on performance except the debug build was 10 mins faster. I'm not sure about a headache, but since the idiomatic Rust approach more than doubled the lines of code, that could be a cabbage winner in the cauliflower category ...
by ejolson
Wed Dec 11, 2019 6:04 pm
Forum: General programming discussion
Topic: Tatami Pi Fun.
Replies: 181
Views: 5621

Re: Tatami Pi Fun.

Though the powerdog function is no more, it seems you left all that floating point still in there. Keeping the algorithm the same definitely makes it easier to see how the programming language affects cabbage. Personal preference, I guess. Simple functions, only called in one place, get inlined. Of...
by ejolson
Wed Dec 11, 2019 4:33 pm
Forum: General programming discussion
Topic: Tatami Pi Fun.
Replies: 181
Views: 5621

Re: Tatami Pi Fun.

Heater wrote:
Fri Nov 29, 2019 4:05 am
Meanwhile one of my partners in our new company has buggered off to Thailand, and the other one is in Bahrain.
I'm having to fix up some code in Python.
Did you ever polish that Rust code sufficiently to post here? How's the Python?
by ejolson
Wed Dec 11, 2019 3:49 pm
Forum: General programming discussion
Topic: Tatami Pi Fun.
Replies: 181
Views: 5621

Re: Tatami Pi Fun.

Did it get slower after the cleaning? Not that I can tell. I do see about a .05 second variance in consecutive runs, same with your C version. Might see a very slight difference using the GCC compare and swap intrinsic vs. the atomic C++ standard class. It is intended more as an example of advanced...
by ejolson
Tue Dec 10, 2019 2:36 am
Forum: General programming discussion
Topic: Tatami Pi Fun.
Replies: 181
Views: 5621

Re: Tatami Pi Fun.

queue.cpp (cleaned up) // queue.cpp -- Compute T(s) from Project Euler Problem 256 // Written December 7, 2019 by Eric Olson // Translated to C++, 2019 by Jean M. Cyr // - Remove/replace redundant variables. // - Scope variables according to their usage. // - Simplify some functions. // - Avoid OMP...
by ejolson
Mon Dec 09, 2019 7:17 pm
Forum: Networking and servers
Topic: Pi 1 B+ as a router
Replies: 4
Views: 254

Re: Pi 1 B+ as a router

mattig wrote:
Mon Dec 09, 2019 7:07 pm
Good to know it can be done at least! Did you use any resources to setup your router?
I followed the official documentation at

https://www.raspberrypi.org/documentati ... s-point.md
by ejolson
Mon Dec 09, 2019 7:14 pm
Forum: General discussion
Topic: How does the Raspberry Pi work?
Replies: 17
Views: 483

Re: How does the Raspberry Pi work?

This question is somewhat similar to "how does a tipper-truck work?" What may not be obvious, given its diminutive size, is that the Raspberry Pi is a real computer that works just like any other. For your report, I would suggest going to the community or school library and checking out some books ...
by ejolson
Mon Dec 09, 2019 7:03 pm
Forum: Troubleshooting
Topic: Random speed slowdown reading files from connected usb hard drive on rpi3 (not a network problem)
Replies: 19
Views: 879

Re: Random speed slowdown reading files from connected usb hard drive on rpi3 (not a network problem)

TLDR : Having problem reading files over network, it randomly slowdowns and causes buffering on the media player, after months of everything working perfectly it suddenly happened. I think it’s a problem with USB Hard Drive itself, I plugged a flash drive and shared it and it didn’t present any pro...
by ejolson
Mon Dec 09, 2019 5:48 pm
Forum: Bare metal, Assembly language
Topic: Raspberry PI 4: CPU too powerful/memory too slow?
Replies: 5
Views: 287

Re: Raspberry PI 4: CPU too powerful/memory too slow?

So we can say that scalar code works faster on RPI4 than on RPI3B/RPI3B+ but simd module is almost useless because it does not give so much benefit. So it only seems to be a bottleneck in memory access according to my observations. On an out-of-order CPU, it appears scalar instructions can make it ...
by ejolson
Mon Dec 09, 2019 4:31 pm
Forum: Networking and servers
Topic: Pi 1 B+ as a router
Replies: 4
Views: 254

Re: Pi 1 B+ as a router

Hello all, So I have an idea for a project, for my little Rasberry Pi 1 B+. Basically, in my local gaming shop, there is no free internet nearby. But there is a very weak signal which I could hop onto. Sadly, for w/e reason, my Linux laptop won't connect to it. (no idea why). So, what I'd like to d...
by ejolson
Mon Dec 09, 2019 4:13 pm
Forum: Bare metal, Assembly language
Topic: Raspberry PI 4: CPU too powerful/memory too slow?
Replies: 5
Views: 287

Re: Raspberry PI 4: CPU too powerful/memory too slow?

The most interesting thing related to Raspberry PI 4 is that SIMD-optimized code gets nearly the same performance as the same scalar code. You may want to check your bare metal program correctly enables the cache. Over the years--possibly due to marketing pressures--processor performance has increa...
by ejolson
Mon Dec 09, 2019 7:45 am
Forum: General programming discussion
Topic: Tatami Pi Fun.
Replies: 181
Views: 5621

Re: Tatami Pi Fun.

The same goes for MEOW™, but Fido only growled when I asked what that meant. Maybe it's like a Pi Zero with retractable claws. After returning from the trademark office, the head of marketing has been acting gloomy. I finally overcame my fear that Fido's bite was worse than the BARK™ and asked, any...
by ejolson
Sun Dec 08, 2019 7:59 pm
Forum: General programming discussion
Topic: Tatami Pi Fun.
Replies: 181
Views: 5621

Re: Tatami Pi Fun.

Oh. That's really starting to look like a bug then. Although past challenges found new bugs in versions of Scheme, Smalltalk, Basic and other languages, this may be the first found in gcc. Maybe, or a bug in the program. MSVC gets divide by 0 here: static int tfree(long k, long l) { long n = l / k;...
by ejolson
Sun Dec 08, 2019 5:40 pm
Forum: General programming discussion
Topic: Tatami Pi Fun.
Replies: 181
Views: 5621

Re: Tatami Pi Fun.

ejolson, ...if only to port Linux and then Rust... To be clear the Rust solution does not need Linux to run. It can run on the barest of bare metal, just like C. Being able to do that is a key design principle of Rust. It a "systems programming language" one can write an OS is Rust. Many are doing ...
by ejolson
Sun Dec 08, 2019 5:28 pm
Forum: General programming discussion
Topic: Tatami Pi Fun.
Replies: 181
Views: 5621

Re: Tatami Pi Fun.

Wouldn't think so... not an OPENMP compile. Oh. That's really starting to look like a bug then. Although past challenges found new bugs in versions of Scheme, Smalltalk, Basic and other languages, this may be the first found in gcc. Maybe, or a bug in the program. MSVC gets divide by 0 here: static...
by ejolson
Sun Dec 08, 2019 4:50 pm
Forum: General programming discussion
Topic: Tatami Pi Fun.
Replies: 181
Views: 5621

Re: Tatami Pi Fun.

jcyr wrote:
Sun Dec 08, 2019 4:43 pm
ejolson wrote:
Sun Dec 08, 2019 4:38 pm
make a difference?
Wouldn't think so... not an OPENMP compile.
Oh. That's really starting to look like a bug then. Although past challenges found new bugs in versions of Scheme, Smalltalk, Basic and other languages, this may be the first found in gcc.
by ejolson
Sun Dec 08, 2019 4:38 pm
Forum: General programming discussion
Topic: Tatami Pi Fun.
Replies: 181
Views: 5621

Re: Tatami Pi Fun.

Haven't dug into it, but... pi@raspberrypi:~/tatami $ gcc -O1 queue.c -lm pi@raspberrypi:~/tatami $ ./a.out Pr(1300)=10657 Floating point exception Unoptimized pi@raspberrypi:~/tatami $ gcc queue.c -lm pi@raspberrypi:~/tatami $ ./a.out Pr(1300)=10657 T(85765680)=200 Lc=557 Hm. Does changing all ins...
by ejolson
Sun Dec 08, 2019 4:25 pm
Forum: General programming discussion
Topic: Tatami Pi Fun.
Replies: 181
Views: 5621

Re: Tatami Pi Fun.

Speaking of which, it would be great to see a mixed-language solution to the tatami challenge created using Pascal with inline ARM assembly. I was thinking a Basic interpreter written in Pascal with GPU inline asm for acceleration, all done in baremetal. VC6 computer shaders are on the way, hoping ...

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